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A Cross-Sectional Study of Occupational Exposure to Trichloroethylene, Chromosomal Aberrations, and Related Biomarkers in Guangdong, China

20 Years
50 Years
Not Enrolling
Immune Function, Chromosome Aberrations

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Trial Information

A Cross-Sectional Study of Occupational Exposure to Trichloroethylene, Chromosomal Aberrations, and Related Biomarkers in Guangdong, China

Trichloroethylene (TCE) is an industrial solvent used in degreasing, dry cleaning, and
numerous other medical and industrial processes. It is a ubiquitous environmental
contaminant of drinking water and is present in many EPA Superfund sites. TCE is a rodent
carcinogen but its carcinogenicity in humans is unclear. There is some evidence for an
elevation in liver and kidney cancers and somewhat more convincing evidence of an
association with non-Hodgkin lymphoma (NHL) in epidemiological studies of occupationally
exposed cohorts. Overall, the carcinogenicity of TCE and its regulation is a matter of
continuing debate despite an extensive database of in vitro and in vivo animal studies and
several cohort and case-control studies. IARC categorizes TCE as a probable human
carcinogen. In order to address questions about TCE's potential carcinogenicity and
mechanism of action in humans, we propose to conduct a cross-sectional study of early
biologic effect biomarkers of genotoxicity and immunotoxicity in 45 workers exposed to
greater than 25 ppm TCE, 30 workers exposed to 10-25 ppm TCE, and 45 unexposed controls in
Guangdong Province, China. We will assess TCE exposure level quantitatively, collect other
exposure information through a questionnaire, collect biological samples, and assay a series
of biomarkers of susceptibility, intermediate and early biologic effects. Our primary goal
is to determine if TCE exposure increases chromosomal aberrations in peripheral lymphocytes,
with a secondary goal of determining if TCE alters levels of key cytokines in plasma and
changes lymphocyte subset ratios. In addition, our collaborators at UC Berkeley will apply a
new generation of cytogenetic and molecular techniques to study TCE's ability to cause
specific types of chromosomal aberrations that have been associated with NHL and related
hematological malignancies as well as the impact of TCE on mRNA expression and the proteome.
The work will compliment previous and ongoing OEEB studies of populations exposed to TCE and
has the potential to make an important contribution to what little is known about the early
biologic effects of TCE in humans.

Inclusion Criteria


A total of 45 workers exposed to greater than 25 ppm TCE, 30 workers exposed from 10 to
less than 25 ppm TCE, and 45 unexposed workers will be enrolled.

We will identify 45 workers from 3 factories who are exposed to greater than 25 ppm TCE.
Our colleagues at the Guangdong NPCC will visit potential study factories and carry out
air measurements for TCE, epichlorhydrin, methylene chloride, perchloroethylene and
benzene. Factories will be selected that use only TCE for degreasing processes, have
minimal co-exposures present in the same part of the workplace where TCE is used, and have
used a stable manufacturing process for the past five years.

Workers will be chosen who work in part of the factory with TCE exposure, have worked for
at least one year in the factory doing the same job in the same part of the manufacturing
process, and have not been exposed to other genotoxic, hematotoxic, or immunotoxic
compounds in any workplace. We will enroll 45 controls, who have no history of
occupational exposure to TCE or to any other genotoxic, hematotoxic or immunotoxic


History of cancer, chemotherapy with DNA-damaging or immunotoxic agents, and medical
treatment with ionizing radiation

Type of Study:


Study Design:


Principal Investigator

Qing Lan, M.D.

Investigator Role:

Principal Investigator

Investigator Affiliation:

National Cancer Institute (NCI)


United States: Federal Government

Study ID:




Start Date:

June 2006

Completion Date:

Related Keywords:

  • Immune Function
  • Chromosome Aberrations
  • Industry Hygiene
  • Molecular Epidemiology
  • Cancer Susceptibility
  • Genotoxicity
  • Immune Function
  • Cancer Susceptability
  • Chromosome Aberrations
  • Chromosome Disorders